This invention relates to cylinder lock mechanisms, more particularly, to mechanisms of the so-called "side bar" type. In further particular, the invention relates to such lock mechanisms in which tumblers are received in a lock cylinder for reciprocal longitudinal movement therein, in the direction of the cylinder axis.
Cylinder lock mechanisms of the side bar type long have been provided. Characteristically, they employ a lock member which is alternately projected from a lock cylinder and retracted for locking and unlocking purposes, respectively, with the locking member engaging a barrel in which the cylinder rotates, for locking purposes. The prior lock mechanisms have both advantages and disadvantages: in particular, their resistance to picking or forcing may be limited.